Enhanced General Packet Radio Service (EGPRS), also known as Enhanced Data rates for GSM Evolution (EDGE), is a digital mobile telephone technology that allows data transmission rates to be increased and improves data transmission reliability.
Two types of an error control method known as Automatic Repeat-reQuest (ARQ) are used in EGPRS, as described in 3GPP TS 43.064—3rd Generation Partnership Project; Technical Specification Group GERAN; Digital cellular telecommunications system (Phase 2+); General Packet Radio Service (GPRS); Overall description of the GPRS radio interface; Stage 2 (Release 5). When a block of data has not been correctly received, the sending entity resends the block of data. The sending entity may be the network or a mobile telephone. The receiving entity may be the network or a mobile telephone. In the first type, blocks of coded data that the receiving entity is unable to successfully decode are resegmented and retransmitted. The receiving entity decodes each retransmission in isolation from the previous transmissions. In the second type, Type II Hybrid ARQ, also known as incremental redundancy (IR), if the receiving entity is unable to successfully decode a block of coded data, that block is retransmitted using a different puncturing scheme. The received bits from the different transmissions are combined to aid the decoding.
It is expected that blocks are not resegmented when using incremental redundancy. Indeed, the EGPRS specifications provide for a “resegment” bit in ARQ control to prevent resegmentation when the network employs incremental redundancy.
It will be appreciated that for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity.